08/24/2009 Evening Primrose

Mrs. Morse and I were chatting about wildflowers a couple of months ago when the subject of primroses came up. She commented on how lovely they were, and I agreed. Then she mentioned that she looked forward to their yellow color, and I got a puzzled look on my face. I told her that the ones I’ve been watching are pink, and they’re already blooming. Mrs. Morse got a puzzled look on her face.

Of course, we had run into the “common name problem.”

It was understandable that Mrs. Morse and I were confused about which flower each other was referencing. There are many “primroses,” and all 64 species in the Oenothera genus have “evening primrose” in their name, as do a number of species in the Camissonia genus .

Oenothera grandis has the USDA ‘national’ common name of “showy evening primrose.” O. grandis is shown on USDA Plants with flowers being pink, white, or yellow, but the University of Texas at Austin calls it one of the yellow evening primroses. Illinoiswildflowers.info doesn’t list O. grandis, and calls O. speciosa “showy evening primrose,” and doesn’t mention the USDA ‘national’ common name of “pinkladies.” Wikipedia calls O. speciosa “pink primrose” and also both “pinkladies” and “showy evening primrose.” O. speciosa has the USDA national name of ‘pinkladies,’ although they are more commonly known as ‘showy evening primrose.’

The range of O. grandis and O. speciosa overlap, but O. grandis is not found in Georgia, where my photos were taken, so that makes my identification of Oenothera speciosa a lot easier. And since a Google search for “showy evening primrose” turns up a lot more references to O. speciosa than O. grandis, I’m quite comfortable with that common name.

Showy Evening Primrose

The name “evening primrose” comes from the fact in many of them open in the evening or during the night, and usually close as the day warms up. Apparently the critters that pollenate these species are active during the cooler part of the day. Or maybe the critters that are active at that time of day are the ones that pollenate these species. While the University of Texas at Austin says it the 1st way, I think it’s more likely the latter.

Oenothera biennis, unlike the showy evening primrose, doesn’t have too much of a name problem if you get beyond simply “primrose.” It’s USDA national name is “common evening primrose,” and it is rarely called by any other name. The “common” in it’s name refers to it’s frequency and distribution, as it is found in all but 7 states (sorry, Lynn – Idaho is one of those 7) rather than a common appearance. You will see this plant along roadsides and in open fields, usually with multiple many-flowered branches separating from the main stem well above the ground, and reaching as high as 7′. When this flower opens in the evening, it is said to give off a lemony aroma.

Common Evening Primrose - Oenothera biennis

And now I’ve circled back around to the puzzled looks on the faces of Mrs. Morse and me. Mrs. Morse was, of course, talking about Oenothera biennis – Common Evening Primrose, a tall yellow beauty, and I was talking about Oenothera speciosa – Showy Evening Primrose, a relatively low-growing pink beauty.